From: foo@...
Date: 2002-04-21T10:51:38+09:00
Subject: blocks vs. Procs, closures as objects?


what follows is not a criticism or even a suggestion... i'm just
ever-curious about language design.  i'm also new to Ruby, so feel
free to correct any mistaken assumptions.


in some other languages which support closures, you can say something
like: 

(define foo 
  (lambda (x) (* x x)))

(foo 3)       => 9

this is a bit like
foo = Proc.new { |x| x * x }
foo.call(3)      => 9


maybe its just that i learned Scheme first, but it suprises me that
you can't say in Ruby:

foo = { |x| x * x }
foo(3)     =>  9

this would seem to me to be the principle-of-least-surprise-est thing
to do.  similarly, i would expect the following to work

{ |x| x * x }.type      => Proc, or Block, or Method, or something...

a block is apparently not an object in ruby, which i guess means that
it's not an expression, either...

anyone care to explain the rationale behind this?

-brian